ASTM F594 covers the chemical and mechanical requirements for stainless steel nuts in diameters ranging from 1/4″ to 1-1/2″ inclusive and for use with fasteners conforming to ASTM F593. These nuts are for general purpose usage, and are available in seven alloy groups. Below is a basic summary of the common grades within the ASTM F594 specification. A number of other less common grades of ASTM F594 exist, but are not detailed in the description below. The Mechanical table here is limited to Alloy groups 1 and 2, as those are the most common and the Chemical table is only showing the most common alloy grades used for their respective alloy groups.
| F594 Alloy Groups | ||||||
|---|---|---|---|---|---|---|
| Alloy Group | Alloy Designation | Alloy Type | ||||
| 1 | 303, 304, 304L, 305, 384, XM1, 18-9LW, 302HQ, 303Se | Austenitic | ||||
| 2 | 316, 316L | Austenitic | ||||
| 3 | 321, 347 | Austenitic | ||||
| 4 | 430, 430F | Ferritic | ||||
| 5 | 410, 416, 416Se | Martensitic | ||||
| 6 | 431 | Martensitic | ||||
| 7 | 630 (17-4) | Precipitation Hardening | ||||
| *The selection of an alloy within each group is at the discretion of the manufacturer unless the purchaser requests a specific alloy. | ||||||
| F594 Mechanical Properties / Condition | ||||||
|---|---|---|---|---|---|---|
| Alloy Group | Condition | Marking | Diameter Range | Proof Stress, Hex Nuts, ksi | Proof Stress, Heavy Hex Nuts, ksi | Rockwell Hardness |
| 1 | AF | F594A | 1/4 to 1-1/2 | 70 | 76 | B85 max |
| A | F594B | 1/4 to 1-1/2 | 75 | 81 | B65 to 95 | |
| CW1 | F594C | 1/4 to 5/8 | 100 | 108 | B95 to C32 | |
| CW2 | F594D | 3/4 to 1-1/2 | 85 | 92 | B80 to C32 | |
| 2 | AF | F594E | 1/4 to 1-1/2 | 70 | 76 | B85 max |
| A | F594F | 1/4 to 1-1/2 | 75 | 81 | B65 to 95 | |
| CW1 | F594G | 1/4 to 5/8 | 100 | 108 | B95 to C32 | |
| CW2 | F594H | 3/4 to 1-1/2 | 85 | 92 | B80 to C32 | |
| F594 Chemical Requirements | ||||||
|---|---|---|---|---|---|---|
| Element, max except as shown | Alloy Group 1, Type 304 | Alloy Group 2, Type 316 | ||||
| Carbon | 0.08% | 0.08% | ||||
| Manganese | 2.00% | 2.00% | ||||
| Phosphorus | 0.045% | 0.045% | ||||
| Sulfur | 0.030% | 0.030% | ||||
| Silicon | 1.00% | 1.00% | ||||
| Chromium | 18.0 to 20.0% | 16.0 to 18.0% | ||||
| Nickel | 8.0 to 10.5% | 10.0 to 14.0% | ||||
| Copper | 1.00% | |||||
| Molybdenum | 2.00 to 3.00% | |||||